#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int n = 0;
	while (scanf("%d", &n) != EOF)
	{
		int num1 = 1;
		int num2 = 1;
		int sum = 1;
		for (int i = 2; i < n; i++)
		{
			sum = num1 + num2;
			num1 = num2;
			num2 = sum;
		}
		printf("%d\n", sum);
	}
	return 0;
}

















